Clutches are employed in a host of applications in which a load must be connected or disconnected from a source of power. In automobiles, manual foot-operated clutches are controlled by the driver to connect and disconnect the engine from a transmission. Hydraulic operated clutches are used in automatic transmissions of vehicles to automatically engage and disengage gears and other apparatus for smooth gear shifting operations. Clutches can also be constructed to be engaged electrically, such as many compressors for automobile air conditioners. Various types of small motorcycles, chainsaws and other equipment utilize centrifugal clutches that automatically engage when the RPM of the engine is increased, and disengage when the engine is at idle speed.
U.S. Pat. Nos. 4,379,502 by Ball et al., and 4,396,102 by Beach, both assigned to the assignee hereof, disclose winch clutches of the type that are manually engaged and manually disengaged.
In yet other machines, it is preferable to manually disengage a clutch to allow the driven part to free wheel, and to self engage when the motor or engine is started or the associated drive shaft begins to rotate. Winches are of such types of machines, where the use of a clutch is advantageous to allow loads to be controlled. For example, in a vehicle-mounted winch of the type which is remotely controlled by way of a wireless device, the operator can manually disengage the clutch to allow the cable or rope to be unwound from the drum and connected to an object to be pulled. The operator need not return to the winch to engage the clutch, but need only start the winch with the wireless remote control, whereupon the clutch automatically engages so that the cable is wound on the drum and the object is moved.
From the foregoing, it can be seen that a need exists for a clutch that is constructed so as to be manually disengaged and which self-engages when the drive force is activated.